A method for preparing a y-type molecular sieve containing mesopores

Abstract

The application discloses a preparation method of Y-type molecular sieve containing mesopores, and comprises the following steps: uniformly mixing a silicon source, a directing agent and a silica alumina gel, then adding an aluminum source and a sodium metaaluminate solution to form a gel, and performing crystallization and post-treatment to obtain the Y-type molecular sieve; the directing agent is obtained by mixing and aging a sodium metaaluminate solution, silicon powder, a silicon source and an alkaline compound; the silica alumina gel is obtained by activating and acid-treating a natural mineral and then mixing and aging the natural mineral with a NaY mother liquor; the sodium metaaluminate solution used in the formation of the gel and the preparation of the directing agent is the same, the sodium metaaluminate solution contains a stabilizer, and the molar ratio of Na2O, Al2O3 and SiO2 in the gel is (1.0-1.9):1:(5-7). The Y-type molecular sieve synthesis method provided by the application can form mesopores without a structure aid or a template agent, and has the advantages of low cost, simple process flow, high quality of the synthesized Y-type molecular sieve and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of molecular sieve synthesis, and particularly relates to a preparation method of Y-type molecular sieve containing mesopores. BACKGROUND

[0002] Y-type zeolite (i.e. Y-type molecular sieve) is widely used in petroleum refining industry due to its developed three-dimensional pore and adjustable acidity. Crystallinity and SiO2 / Al2O3 ratio are the main factors affecting the properties and functions of Y-type zeolite. The mature production method of Y-type molecular sieve at present mostly adopts the directing agent method proposed by US Grace Company in US3639099 and US3671191, which can synthesize Y-type molecular sieve products with crystallinity of more than 83% and SiO2 / Al2O3 ratio of about 5.0 within 28 hours.

[0003] In order to improve the reaction performance of Y-type molecular sieve, the pore structure of Y-type molecular sieve is mostly improved. The methods for improving the pore structure of Y-type molecular sieve are roughly divided into pore forming in the synthesis process and pore forming by post-modification. The pore forming in the synthesis process generally adds different substances and forms mesopores in the synthesis process by using a template method, and the pore forming by post-modification generally adopts chemical method, hydrothermal ultrastability method, hydrothermal ultrastability-acid treatment method and other methods. At present, the hydrothermal ultrastability method is mostly used in industry. Through hydrothermal ultrastability, part of the framework aluminum of the molecular sieve is removed, the Al in Si-O-Al is replaced by Si, the acid center density of the active component Y-type molecular sieve is reduced, the acid strength is increased, and more importantly, the molecular sieve has more abundant secondary pores through the hydrothermal ultrastability modification process, and the existence of the secondary pores improves the mass transfer and diffusion of macromolecular reactants and the accessibility of the inner pore surface active center, thereby bringing better reaction results. However, the framework of the molecular sieve after hydrothermal ultrastability is significantly damaged, and a large amount of non-framework aluminum is formed to block the pore, which is more prone to form coke on the surface of the catalyst, which is not conducive to the reaction. Therefore, many researchers adopt acid dealumination to control the acidity of the catalyst and clean the pores of the catalyst.

[0004] Grace company used inorganic template method to add cesium ion in reactant gel and conventional method to synthesize octahedral molecular sieve CSZ-1, CSZ-3, etc., hoping to improve the pore structure of molecular sieve (USP4333859, USP4309313), but the cesium ion in the product is not easy to remove, and needs to be exchanged and calcined for many times. The organic template is usually removed by high temperature calcination method, which cannot be recycled, increases the synthesis cost, and brings environmental burden. In addition, the template method for synthesizing Y-type molecular sieve needs long crystallization time, and the secondary utilization of template is still a difficult problem. The so-called template-free direct synthesis method refers to not adding template in any preparation process of preparation of directing agent, gel and crystallization, but through adjusting the conditions of preparation system, adding different functional components, etc., so as to achieve the purpose of improving the product mesopore. Therefore, from the synthesis process, the mesopore becomes an important method to improve the pore structure of Y-type molecular sieve.

[0005] For example, Chinese patent document CN109665539B re-slurries the pre-formed Y-type molecular sieve, then mixes it with a silane coupling agent and a quaternary ammonium salt surfactant, and reacts it at a temperature of 60–200℃ and under autogenous pressure for 4–48 hours to obtain NaY molecular sieve. This method creates certain mesopores through the volatilization of organic matter, but the synthesis under these conditions will release a large amount of organic matter, affecting the environment. Chinese patent document CN104891523A also discloses a method for preparing mesoporous Y-type molecular sieves using a template agent. Chinese patent document CN101468801 discloses the use of modified bentonite for activation and modification, and then replacing part of the silicon and aluminum source to prepare Y-type molecular sieves, resulting in a mesopore volume of 0.10–0.40 mL / g for the Y-type molecular sieves; this method uses modified bentonite as part of the silicon and aluminum source. Chinese patent document CN114426286A discloses a method for obtaining mesoporous Y-type molecular sieves through repeated hydrothermal crystallization. Chinese patent document CN114956117A discloses a method for synthesizing mesoporous molecular sieves by supplementing the mother liquor with a template agent. Chinese patent document CN113149028A discloses a method for preparing NaY molecular sieves using activated silica powder and for recycling the mother liquor, including the following steps: S1. Preparation of activated silica powder: Select one or more of waste FCC catalyst, bentonite, kaolin, and fly ash, add hydrochloric acid or sulfuric acid at 1.0-1.5 times the theoretical acid consumption, stir and acidify for 1-6 hours, filter and separate, and reserve the solution for use in preparing finished products such as polyaluminum chloride; the solid, after washing, becomes activated silica slag, which is dried and pulverized to obtain activated silica powder; S2. Preparation of NaY molecular sieve crystallization directing agent; S 3. Gel Formation: Activated silica powder, low-alkali sodium aluminate, and a guiding agent are mixed in a certain proportion and stirred uniformly at 10-80℃ for 0.5-5 hours. Then, a calculated amount of water is added to achieve a total molar ratio of Na₂O:Al₂O₃:SiO₂:H₂O = 2-6:1:8-15:90-350. The mixture is stirred at 10-60℃ for 0.5-5 hours. 4. Crystallization: The mixture is crystallized in a reactor at 80-120℃ for 6-48 hours. After filtration, washing, and drying, the product NaY is obtained, and the mother liquor after filtration is collected. This method uses the treated silica powder as a silicon source, but it suffers from complex preparation processes and difficult filtration. Furthermore, the quality of the Y-type molecular sieve obtained using this synthesis method is lower than that of the conventional gel method, and impurities appear, making it unsuitable for continuous industrial processes.

[0006] Chinese patent documents CN101767799A, CN1621348A, CN1621349A, CN101254929A all disclose the preparation method of NaY molecular sieve by two-stage or multi-stage crystallization. However, the above-mentioned preparation methods of NaY molecular sieve mainly involve how to improve the silicon-aluminum ratio, and there is no mention of preparing mesopores for NaY molecular sieve by synthesis. Chinese patent document CN110862096A adopts a preparation method of synthesizing NaY using a water glass dispersion treated guiding gel, and the prepared NaY molecular sieve has high silicon-aluminum ratio, good hydrothermal stability, large pore size and high specific surface area. However, this method needs to prepare a guiding gel first, and the process flow is long and complex.

[0007] In addition, there are also methods of realizing mesoporous structure by post-modification. For example, Chinese patent document CN110862097A discloses a method of combining multiple hydrothermal ultrastable, calcination and acid treatment to make the pore volume of Y-type molecular sieve reach 0.40 mL / g or more, but there are problems such as complicated steps and high cost. CN111099615B discloses obtaining mesoporous molecular sieve by fully contacting Y molecular sieve and ordered mesoporous directing agent under certain conditions. CN110540213A discloses obtaining Y molecular sieve with surface rich in mesopores by repeated ammonium exchange. CN114713271A discloses preparing mesopores by mixing at least one of methylamine, ethylamine, ethylenediamine, 1-propylamine and isopropylamine with Y-type molecular sieve. CN107973313B discloses obtaining mesoporous Y-type molecular sieve by multiple treatments of organic acid, sodium hydroxide and ammonium nitrate. CN106927481A and CN106927477A both report a method of obtaining Y-type molecular sieve containing mesopores by mixing Y-type molecular sieve with glycerol, and then treating with an inorganic directing agent, a quaternary ammonium compound, ethanol and cellulose at a certain temperature and time. CN110871102A discloses obtaining a composite structure molecular sieve by in-situ growing aluminum oxide on Y-type molecular sieve, CN115594193A discloses obtaining mesoporous Y-type molecular sieve by simultaneously de-alumination, mesopore formation and lattice shrinkage under the treatment of high-temperature acid vapor in an oxygen-free environment, CN107777697B discloses preparing Y-type molecular sieve containing mesopores by alkali treatment. CN101108736 discloses a method of treating with dilute acid combined with recrystallization of silicon source to form mesopores, CN104760973A discloses preparing Y-type molecular sieve with ultra-high mesopore content by gas phase ultrastable method, CN114477217A discloses treating with ammonium fluosilicate or hydrofluoric acid, CN111086999A and CN106672997B report a method of modifying pores at high temperature and high pressure, and CN109775716A, CN112661166B and CN112850742A respectively disclose a method of obtaining mesopores by treating with organic base and calcining after mixing multiple template solutions.

[0008] In summary, the Y-type molecular sieve forms a multi-stage pore or mesopore in the synthesis stage, which is mainly realized by introducing organic or inorganic templates, structure aids, and the like, and there are problems such as high cost, difficulty in implementation, environmental problems caused by removal of templates, and difficulty in industrial continuous implementation, and the like, and the mesopore modification mainly concentrates on acid-base pretreatment, chemical dealumination such as ammonium fluorosilicate dealumination and gas phase ultrastable dealumination, and the like, and there are problems such as a complex process flow and a heavy degree of destruction of crystallinity. SUMMARY

[0009] Based on the problems existing in the prior art and the direction for improvement, the present application provides a preparation method of a Y-type molecular sieve containing a mesopore, and compared with the existing synthesis method of the Y-type molecular sieve forming a multi-stage pore or mesopore in the synthesis stage, the Y-type molecular sieve synthesis method provided by the present application can form a mesopore without a structure aid or template, and has the advantages of low cost, a simple process flow, and high quality of the synthesized Y-type molecular sieve.

[0010] To achieve the above object, the present application provides the following technical scheme:

[0011] A preparation method of a Y-type molecular sieve containing a mesopore, comprising the following steps:

[0012] After the silicon source, the directing agent and the silica alumina gel are uniformly mixed, the aluminum source and the sodium metaaluminate solution are sequentially added to form a gel, and the Y-type molecular sieve is obtained through crystallization and post-treatment;

[0013] The directing agent is obtained by mixing and aging a sodium metaaluminate solution, silicon powder, water glass and an alkaline compound;

[0014] The silica alumina gel is obtained by mixing and aging a natural mineral after activation and acid treatment and a NaY mother liquor;

[0015] The sodium metaaluminate solution used in the formation of the gel and the preparation of the directing agent is the same, the sodium metaaluminate solution contains a stabilizer, the concentration of Al2O3 is 190-400 g / L, the concentration of Na2O is 210-400 g / L, and the molar ratio of Na2O to Al2O3 is controlled to be 0.86-3.46:1.

[0016] The molar ratio of Na2O to Al2O3 to SiO2 in the gel is (1.0-1.9):1:(5-7).

[0017] Optionally, in the preparation method of the Y-type molecular sieve containing a mesopore provided by the present application, in the preparation process of the silica alumina gel, the acid treatment is to treat the activated natural mineral with an acid solution at pH 2.8-6.0 and 20-100℃ for 10-90 min;

[0018] The concentration of the acid solution is 0.1-15 mol / L,

[0019] The liquid-solid ratio of the activated natural mineral and the acid solution is 4-15.

[0020] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the application, the activation temperature in the preparation of the silica-alumina gel is 600-900°C, and the time is 20-100 min.

[0021] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the application, the aging temperature in the preparation of the silica-alumina gel is 20-100°C, and the time is 10-240 min.

[0022] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the application, the SiO2 concentration in the NaY mother liquor is 40-65 g / L, and the Na2O concentration is 20-40 g / L.

[0023] The mass data of the silica-alumina gel are as follows: SiO2 50%-65%, Al2O3 15%-20%, Na2O 12%-15%, solid content 10%-50%, and density 1.0-1.4.

[0024] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the application, the natural mineral is selected from one or more of soft and hard kaolinite, coal-based kaolinite, halloysite, attapulgite, sepiolite and palygorskite.

[0025] The acid solution is selected from an inorganic acid solution or an organic acid solution, the inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and the organic acid is selected from one or more of formic acid, citric acid, oxalic acid and acetic acid.

[0026] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the application, the sodium aluminate solution is obtained by stirring 25wt%-50wt% sodium hydroxide solution and aluminum hydroxide powder with an Al2O3 content of not less than 60wt% at 0.1-0.4 MPa and 100-140°C for 2-6 hours, and then adding a stabilizer.

[0027] Optionally, in the preparation of the sodium aluminate solution provided by the application, the stabilizer is selected from one or more of sodium carbonate, sodium bicarbonate and ammonia water.

[0028] The added mass of the stabilizer is 1%-10% based on 100% of the total mass of the sodium hydroxide solution and the aluminum hydroxide powder.

[0029] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the molar ratio of Na2O, Al2O3 and SiO2 in the directing agent is (10-20):1:(10-20).

[0030] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the preparation of the directing agent comprises the following steps: adding the basic compound and the silicon powder into the sodium aluminate solution, and then adding the silicon source after uniform mixing, and then standing and aging at 30-40℃ for 6-24 hours.

[0031] Optionally, in the preparation process of the directing agent in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the basic compound is selected from any one of sodium hydroxide, sodium carbonate and sodium bicarbonate;

[0032] The mass ratio of the basic compound to the directing agent is 0.01-0.1, calculated based on Al2O3;

[0033] The molar ratio of the silicon powder to the directing agent is 0.01-0.2, calculated based on SiO2.

[0034] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the content of the directing agent is 1wt%-30wt%, preferably 1wt%-20wt%, calculated based on the mass of the gel as 100%.

[0035] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the post-treatment comprises the steps of separation, washing and drying; the washing step is performed using deionized water, and the washing is performed until the pH value of the filtrate is 10.0-10.5.

[0036] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the crystallization is hydrothermal crystallization, the temperature of the hydrothermal crystallization is 90-100℃, and the time is 16-40h.

[0037] Optionally, in the preparation method of the Y-type molecular sieve containing mesopores provided by the present application, the silicon source is selected from one or more of the following: silicon-aluminum powder, silica sol, water glass, white carbon black and sodium silicate; the SiO2 concentration of the water glass is 260-350g / L, and the modulus is 2.96-3.40.

[0038] The aluminum source is selected from one or more of the following: aluminum sulfate, aluminum phosphate, aluminum chloride, aluminum nitrate, aluminum fluoride, aluminum formate and aluminum acetate.

[0039] Optionally, the preparation method of the Y-type molecular sieve containing mesopores provided by the present application comprises the following steps:

[0040] The directing agent and the silica-alumina gel are added into the silicon source slowly and successively, and then mixed uniformly (for example, mixed for 30-60 minutes), and then the aluminum source is added and mixed fully (for example, mixed for 30-60 minutes), and finally the sodium metaaluminate solution is added to form a gel, and then the gel is crystallized, filtered, washed, and dried to obtain the Y-type molecular sieve.

[0041] Compared with the prior art, the Y-type molecular sieve provided by the present application has the following beneficial effects:

[0042] Beneficial effect 1: The preparation method of the Y-type molecular sieve containing mesopores provided by the present application breaks through the problem of poor stability of the main raw material sodium metaaluminate solution by mutual cooperation between each raw material step, and combines with a low-sodium gel formula, so that the total synthesis cost can be reduced by 30-50% and the salt discharge can be reduced by 40-50% compared with a conventional formula.

[0043] Beneficial effect 2: The preparation method of the Y-type molecular sieve containing mesopores provided by the present application changes the traditional idea of adding an organic template or an inorganic compound, and uses a modified natural mineral to not only provide a silicon-aluminum source, but also to age with a crystallization mother liquor to prepare a molecular sieve precursor and a structure unit, so that a high-quality Y-type molecular sieve (with a silicon-aluminum ratio of 5.2 or more, a crystallinity of 90-99%, and a total pore volume of 0.4-0.5 mL / g) can be synthesized by hydrothermal crystallization, and the industrial application is successfully realized.

[0044] Specifically, 1) in the prior art, to realize the pore-forming of Y-type molecular sieve, mostly the post-modification method is adopted, that is, Y-type molecular sieve is synthesized first, and then modified and pore-formed. Not only the process flow is long, but also the processing cost is high. In the present application, the product rich in active alumina after activation and acid treatment of natural mineral is combined with NaY mother liquor to form silica-alumina gel with multi-level pore distribution, and the mass transfer and combined growth of silica and alumina in the synthesis process are strengthened. Not only the pore structure of Y-type molecular sieve is improved in situ, but also the utilization rate of NaY mother liquor is improved after aging of the crystal mother liquor, and the process steps are effectively saved and the cost is reduced. 2) In the traditional Y-type molecular sieve synthesis process, different concentrations of sodium metaaluminate solution are used in the configuration process of the directing agent and the preparation process of the gel, which increases the complexity of the process operation, energy consumption and consumption of various raw materials. In the present application, only one concentration of sodium metaaluminate solution is used when preparing the directing agent and the gel, which reduces the introduction of sodium and the types of synthesis solution from the source, thereby reducing the ions such as sodium and sulfate ions that may form salts brought in by synthesis, and greatly reducing the energy consumption, consumption of various raw materials and transportation of the production enterprises, and significantly reducing the synthesis cost. 3) Sodium metaaluminate solution is a very important aluminum source in the synthesis of Y-type molecular sieve. Under conventional conditions, the preparation of the solution strictly controls the temperature, and the concentration control of the ratio of sodium oxide to aluminum oxide in the solution is very strict. Moreover, the stability of sodium metaaluminate solution is poor, and the storage time is generally not more than 72 hours, which greatly limits the efficiency of synthesis and causes waste of energy and raw materials. Sodium metaaluminate exists in the form of Na[Al(OH)4] (sodium tetrahydroxy aluminate) in aqueous solution, which is in an unstable state and is prone to precipitate in the form of Al(OH)3, causing the decomposition and deterioration of sodium metaaluminate solution. The present application starts from the root cause of the poor stability of sodium metaaluminate solution, and adds a stabilizer. The stabilizer dissociates OH - in the solution to prevent the decomposition of Na[Al(OH)4], so as to achieve the purpose of stabilizing the sodium metaaluminate solution, make the prepared sodium metaaluminate solution more stable and conducive to storage and transportation, reduce the cost of raw materials and production, and at the same time reduce the amount of waste water and waste residue. 4) In the present application, silicon powder is added to the directing agent, which not only plays the role of supplementing silicon source, but more importantly, after the addition of silicon powder, numerous "silicon islands" are formed. In the aging stage of the directing agent, aluminum ions are more easily adsorbed on the silicon islands to form the initial structure unit of silicon and aluminum, thereby increasing the crystal nucleus, promoting the growth of the crystal, and increasing the relative crystallinity of the molecular sieve. 5) On the basis of the above three raw materials, a gel with even lower sodium is used, the utilization rate of silica and alumina source is high, the crystallization time is short, the whole process operation is simple and efficient, and the Y-type molecular sieve prepared has high crystallinity and developed pore structure. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 XRD pattern of the Y-type molecular sieve prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0046] The application will be described in detail below by way of examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the scope of protection of the application, and those skilled in the art can make some non-essential improvements and adjustments to the application according to the above description of the application.

[0047] The specific experimental steps or conditions not specified in the examples and comparative examples can be carried out according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments not specified by the manufacturer are all conventional reagent products that can be obtained by purchase.

[0048] Source of raw materials or equipment: (including raw material name, specification, manufacturer, etc.)

[0049] Sodium silicate: industrial product, from Lanzhou Petrochemical Company Catalyst Department (SiO2: 19.60%, Na2O: 6.86%)

[0050] Sodium metaaluminate: industrial product, from Lanzhou Petrochemical Company Catalyst Department (Na2O: 12.10%, Al2O3: 8.06%)

[0051] Aluminum sulfate: industrial product, from Lanzhou Petrochemical Company Catalyst Department (Al2O3: 7.10%)

[0052] Sodium hydroxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum phosphate, aluminum nitrate, aluminum acetate, aluminum formate, aluminum fluoride, sodium carbonate, sodium bicarbonate, silica sol, soft kaolin, hard kaolin, coal-based kaolin, halloysite, attapulgite, sepiolite, palygorskite, sulfuric acid, hydrochloric acid, phosphoric acid, formic acid, citric acid, oxalic acid, acetic acid: chemical pure, National Pharmaceutical Group Chemical Reagent Co., Ltd.

[0053] Silicon powder: chemical pure, Qingdao Jinyang Fine Chemical Co., Ltd.

[0054] Preparation of sodium metaaluminate solution

[0055] Sodium metaaluminate solution 1: 25wt% sodium hydroxide solution and aluminum hydroxide powder with Al2O3 content of 60wt% were reacted in an autoclave at 0.4MPa and 140℃ for 6 hours, the molar ratio of Al2O3 to Na2O was controlled to be 1:0.86, the Al2O3 concentration in the sodium metaaluminate solution was 400g / L, and the Na2O concentration was 210g / L. Then 1% solid sodium hydroxide based on the total mass of the sodium metaaluminate solution was added, and the mixture was stirred thoroughly for use.

[0056] Sodium metaaluminate solution 2: 50wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 80wt% in an autoclave at 0.1 MPa, 100°C for 2 hours, controlling the molar ratio of Al2O3, Na2O to be 1:3.46, the Al2O3 concentration in the sodium metaaluminate solution was 190g / L, and the Na2O concentration was 400g / L. Then 5% of solid sodium bicarbonate by mass of the total sodium metaaluminate solution was added, and mixed well for use.

[0057] Sodium metaaluminate solution 3: 40wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 90wt% in an autoclave at 0.3 MPa, 100°C for 2 hours, controlling the molar ratio of Al2O3, Na2O to be 1:1.08, the Al2O3 concentration in the sodium metaaluminate solution was 380g / L, and the Na2O concentration was 250g / L. Then 10% of solid sodium carbonate by mass of the total sodium metaaluminate solution was added, and mixed well for use.

[0058] Sodium metaaluminate solution 4: 30wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 95wt% in an autoclave at 0.2 MPa, 100°C for 4 hours, controlling the molar ratio of Al2O3, Na2O to be 1:84, the Al2O3 concentration in the sodium metaaluminate solution was 250g / L, and the Na2O concentration was 280g / L. Then 8% of ammonia solution (20% mass concentration) by mass of the total sodium metaaluminate solution was added, and mixed well for use.

[0059] Sodium metaaluminate solution 5: 35wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 95wt% in an autoclave at 0.1 MPa, 120°C for 5 hours, controlling the molar ratio of Al2O3, Na2O to be 1:2.08, the Al2O3 concentration in the sodium metaaluminate solution was 210g / L, and the Na2O concentration was 265g / L. Then 7% of ammonia solution (20% mass concentration) by mass of the total sodium metaaluminate solution was added, and mixed well for use.

[0060] Sodium metaaluminate solution 6: 45wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 60wt% in an autoclave at 0.4 MPa, 140°C for 2 hours, controlling the molar ratio of Al2O3, Na2O to be 1:1.65, the Al2O3 concentration in the sodium metaaluminate solution was 300g / L, and the Na2O concentration was 300g / L. Then 3% of solid sodium hydroxide by mass of the total sodium metaaluminate solution was added, and mixed well for use.

[0061] Sodium metaaluminate solution 7: 33wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 70wt% in an autoclave at 0.3MPa, 130°C for 3 hours, the molar ratio of Al2O3, Na2O was controlled to be 1:1.88, the Al2O3 concentration in the sodium metaaluminate solution was 280g / L, and the Na2O concentration was 320g / L. Then, 2% of solid sodium bicarbonate in the total mass of the sodium metaaluminate solution was added, and the mixture was fully stirred and mixed for use.

[0062] Sodium metaaluminate solution 8: 37wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 77wt% in an autoclave at 0.2MPa, 110°C for 5 hours, the molar ratio of Al2O3, Na2O was controlled to be 1:1.72, the Al2O3 concentration in the sodium metaaluminate solution was 330g / L, and the Na2O concentration was 345g / L. Then, 4% of solid sodium carbonate in the total mass of the sodium metaaluminate solution was added, and the mixture was fully stirred and mixed for use.

[0063] Sodium metaaluminate solution 9: 32wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 73wt% in an autoclave at 0.1MPa, 135°C for 5 hours, the molar ratio of Al2O3, Na2O was controlled to be 1:1.79, the Al2O3 concentration in the sodium metaaluminate solution was 350g / L, and the Na2O concentration was 380g / L. Then, 6% of ammonia solution (20% mass concentration) in the total mass of the sodium metaaluminate solution was added, and the mixture was fully stirred and mixed for use.

[0064] Sodium metaaluminate solution 10: 25wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with Al2O3 content of 72wt% in an autoclave at 0.1MPa, 135°C for 6 hours, the molar ratio of Al2O3, Na2O was controlled to be 1:1.69, the Al2O3 concentration in the sodium metaaluminate solution was 365g / L, and the Na2O concentration was 375g / L. Then, 9% of solid sodium hydroxide in the total mass of the sodium metaaluminate solution was added, and the mixture was fully stirred and mixed for use.

[0065] Preparation of silica-alumina gel

[0066] The element content in the silica-alumina gel was calculated after being determined by chemical titration method, and the density was determined by a pycnometer.

[0067] Silica-alumina gel 1: 900 g of coal-series kaolin was activated at 900℃ for 120 min, mixed with 15 mol / L formic acid solution, treated at 100℃ for 90 min with liquid-solid ratio of 4 and pH value of 2.8, then slowly added with NaY mother liquor with SiO2 concentration of 40 g / L and Na2O concentration of 20 g / L, aged at 30℃ for 240 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO2 50%, Al2O3 15%, Na2O 12%, solid content 46%, and density 1.1.

[0068] Silica-alumina gel 2: 500 g of soft kaolin was activated at 600℃ for 100 min, mixed with 0.1 mol / L hydrochloric acid solution, treated at 50℃ for 10 min with liquid-solid ratio of 15 and pH value of 3.9, then slowly added with NaY mother liquor with SiO2 concentration of 60 g / L and Na2O concentration of 30 g / L, aged at 100℃ for 10 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO2 65%, Al2O3 20%, Na2O 14%, solid content 21%, and density 1.4.

[0069] Silica-alumina gel 3: 300 g of eriochite was activated at 700℃ for 20 min, mixed with 3 mol / L sulfuric acid solution, treated at 80℃ for 30 min with liquid-solid ratio of 10 and pH value of 3.5, then slowly added with NaY mother liquor with SiO2 concentration of 52 g / L and Na2O concentration of 23 g / L, aged at 80℃ for 30 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO2 60%, Al2O3 18%, Na2O 13%, solid content 33%, and density 1.1.

[0070] Silica-alumina gel 4: 400 g of attapulgite was activated at 800℃ for 80 min, mixed with 10 mol / L citric acid solution, treated at 60℃ for 60 min with liquid-solid ratio of 8 and pH value of 4.1, then slowly added with NaY mother liquor with SiO2 concentration of 41 g / L and Na2O concentration of 32 g / L, aged at 50℃ for 200 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO2 58%, Al2O3 16%, Na2O 12%, solid content 20%, and density 1.23.

[0071] Silica-alumina gel 5: 300 grams of sepiolite was activated at 650°C for 40 min, mixed with 5 mol / L phosphoric acid solution, treated at 70°C for 70 min with liquid-solid ratio of 13 and pH value of 4.5, then slowly added with NaY mother liquor with SiO2 concentration of 44 g / L and Na2O concentration of 24 g / L, aged at 50°C for 150 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO263%, Al2O319%, Na2O 12%, solid content 10%, and density 1.13.

[0072] Silica-alumina gel 6: 500 grams of palygorskite was activated at 750°C for 60 min, mixed with 8 mol / L oxalic acid solution, treated at 40°C for 20 min with liquid-solid ratio of 6 and pH value of 4.8, then slowly added with NaY mother liquor with SiO2 concentration of 53 g / L and Na2O concentration of 27 g / L, aged at 70°C for 100 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO262%, Al2O315%, Na2O 12%, solid content 32%, and density 1.33.

[0073] Silica-alumina gel 7: 600 grams of hard kaolin was activated at 850°C for 30 min, mixed with 2 mol / L acetic acid solution, treated at 90°C for 40 min with liquid-solid ratio of 14 and pH value of 5.7, then slowly added with NaY mother liquor with SiO2 concentration of 43 g / L and Na2O concentration of 23 g / L, aged at 50°C for 170 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO258%, Al2O315%, Na2O 12%, solid content 18%, and density 1.17.

[0074] Silica-alumina gel 8: 300 grams of soft kaolin was activated at 700°C for 70 min, mixed with 14 mol / L citric acid solution, treated at 30°C for 90 min with liquid-solid ratio of 12 and pH value of 5.9, then slowly added with NaY mother liquor with SiO2 concentration of 45 g / L and Na2O concentration of 25 g / L, aged at 60°C for 130 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO259%, Al2O317%, Na2O 12%, solid content 25%, and density 1.25.

[0075] Silica-alumina gel 9: 500 g of erionite was activated at 600 °C for 50 min, mixed with 4 mol / L phosphoric acid solution, treated at 80 °C for 50 min with liquid-solid ratio of 4 and pH value of 3.0, then slowly added with NaY mother liquor with SiO2 of 64 g / L and Na2O concentration of 30 g / L, aged at 90 °C for 60 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO2 64%, Al2O3 19%, Na2O 14%, solid content 10%, and density 1.10.

[0076] Silica-alumina gel 10: 300 g of sepiolite was activated at 800 °C for 90 min, mixed with 12 mol / L oxalic acid solution, treated at 50 °C for 90 min with liquid-solid ratio of 7 and pH value of 3.3, then slowly added with NaY mother liquor with SiO2 of 56 g / L and Na2O concentration of 26 g / L, aged at 20 °C for 90 min, and then prepared into silica-alumina gel through filtration and washing. The mass data of the silica-alumina gel are as follows: SiO2 55%, Al2O3 16%, Na2O 12%, solid content 26%, and density 1.34.

[0077] Preparation of directing agent

[0078] Directing agent 1: 100 g of the above fresh sodium metaaluminate solution 1 was weighed, and silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent was 0.2), water glass, and solid sodium hydroxide (calculated as alumina, the amount of the alkali added accounted for 1% of the total mass of the directing agent) were added thereto. The mixture was aged at 35 °C for 23 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 10:1:10.

[0079] Directing agent 2: 130 g of the above fresh sodium metaaluminate solution 2 was weighed, and silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent was 0.1), water glass, and solid sodium carbonate (calculated as alumina, the amount of the alkali added accounted for 10% of the total mass of the directing agent) were added thereto. The mixture was aged at 30 °C for 20 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 20:1:20.

[0080] Directing agent 3: 180 g of the above fresh sodium metaaluminate solution 3 was weighed, and silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent was 0.01), water glass, and solid sodium bicarbonate (calculated as alumina, the amount of the alkali added accounted for 5% of the total mass of the directing agent) were added thereto. The mixture was aged at 33 °C for 18 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 20:1:15.

[0081] Directing agent 4: 140 g of the above fresh sodium metaaluminate solution 4 was weighed out and silicon powder (molar ratio of silicon powder to directing agent was 0.03 in terms of SiO2), water glass and solid sodium carbonate (the amount of the base added was 8% of the total mass of the directing agent in terms of alumina) were added thereto, and it was left to stand and age for 16 hours at 30°C to produce a directing agent having a molar ratio of Na2O, Al2O3 and SiO2 of 15:1:10.

[0082] Directing agent 5: 170 g of the above fresh sodium metaaluminate solution 5 was weighed out and silicon powder (molar ratio of silicon powder to directing agent was 0.15 in terms of SiO2), water glass and solid sodium hydroxide (the amount of the base added was 6% of the total mass of the directing agent in terms of alumina) were added thereto, and it was left to stand and age for 12 hours at 37°C to produce a directing agent having a molar ratio of Na2O, Al2O3 and SiO2 of 15:1:20.

[0083] Directing agent 6: 130 g of the above fresh sodium metaaluminate solution 6 was weighed out and silicon powder (molar ratio of silicon powder to directing agent was 0.18 in terms of SiO2), water glass, solid sodium carbonate (the amount of the base added was 4% of the total mass of the directing agent in terms of alumina) were added thereto, and it was left to stand and age for 8 hours at 40°C to produce a directing agent having a molar ratio of Na2O, Al2O3 and SiO2 of 10:1:20.

[0084] Directing agent 7: 200 g of the above fresh sodium metaaluminate solution 7 was weighed out and silicon powder (molar ratio of silicon powder to directing agent was 0.05 in terms of SiO2), water glass and solid sodium bicarbonate (the amount of the base added was 3% of the total mass of the directing agent in terms of alumina) were added thereto, and it was left to stand and age for 13 hours at 32°C to produce a directing agent having a molar ratio of Na2O, Al2O3 and SiO2 of 18:1:16.

[0085] Directing agent 8: 400 g of the above fresh sodium metaaluminate solution 8 was weighed out and silicon powder (molar ratio of silicon powder to directing agent was 0.08 in terms of SiO2), water glass and solid sodium carbonate (the amount of the base added was 9% of the total mass of the directing agent in terms of alumina) were added thereto, and it was left to stand and age for 10 hours at 36°C to produce a directing agent having a molar ratio of Na2O, Al2O3 and SiO2 of 13:1:18.

[0086] Directing agent 9: 500 g of the above fresh sodium metaaluminate solution 9 was weighed out and silicon powder (molar ratio of silicon powder to directing agent was 0.17 in terms of SiO2), water glass and solid sodium bicarbonate (the amount of the base added was 7% of the total mass of the directing agent in terms of alumina) were added thereto, and it was left to stand and age for 22 hours at 38°C to produce a directing agent having a molar ratio of Na2O, Al2O3 and SiO2 of 19:1:13.

[0087] Directing agent 10: 300g of the above fresh sodium metaaluminate solution 10 was weighed and silicon powder (molar ratio of silicon powder to directing agent was 0.12 in terms of SiO2), water glass, solid sodium hydroxide (in terms of alumina, the amount of the base added accounted for 2% of the total mass of the directing agent) were added thereto, and the mixture was aged at 31℃ for 24 hours to prepare a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 12:1:17.

[0088] Specific analysis method:

[0089] The crystallinity of the Y-type molecular sieve was determined by X-ray diffraction method on a D / max-3C X-ray powder diffractometer manufactured by Rigaku Company of Japan, and the specific operation method referred to the standard Q / SYLS 0596-2002.

[0090] The silicon-aluminum ratio of the Y-type molecular sieve was tested by X-ray powder diffraction method, and the specific operation method referred to the standard Q / SYLS 0573-2002.

[0091] The total pore volume of the Y-type molecular sieve was determined by using an ASAP 2460 full-automatic specific surface analyzer of Micromeritics Company of the United States.

[0092] Example 1

[0093] The embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0094] 500g of silica sol was weighed, 400g of the above silica-alumina sol 1 was slowly added, 123g of the above directing agent 1 was further added, and after being fully stirred for 30min, an aluminum sulfate solution with a concentration of 88g / L was slowly added, and after being stirred for 20min, the sodium metaaluminate solution 1 was finally added to form a gel, and the molar ratio of Na2O, Al2O3 and SiO2 in the gel was controlled to be 1:1:6; after being rapidly stirred for 30min, the gel was transferred into a synthesis kettle, and was crystallized at 100℃ for 40 hours; the obtained solid was washed with deionized water until the pH of the washing liquid was 10.5, and then was dried at 120℃ for 12h to obtain the Y-type molecular sieve.

[0095] The Y-type molecular sieve was subjected to XRD test, and the results are shown in Figure 1 As shown in Figure 1 It can be known that the molecular sieve prepared in the embodiment has complete crystal form and does not contain other impurity crystals.

[0096] Example 2

[0097] The embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0098] Take 200g white carbon black, slowly add 100g of the above silicon aluminum glue 2, add 78g of the above directing agent 2, stir for 30min, then slowly add aluminum chloride, stir for 20min, and finally add sodium aluminate solution 2 to form a gel, and control the molar ratio of Na2O, Al2O3 and SiO2 in the gel to be 1.9:1:5.7; After stirring for 30min, transfer into the synthesis kettle, crystallize at 96℃ for 36h, filter the obtained solid, wash with deionized water until the pH of the washing liquid is 10.2, then dry at 120℃ for 12h to obtain Y-type molecular sieve.

[0099] Example 3

[0100] The embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0101] Take 300g water glass, slowly add 140g of the above silicon aluminum glue 3, add 112g of the above directing agent 3, stir for 30min, then slowly add aluminum phosphate, stir for 20min, and finally add the above fresh sodium aluminate solution 3 to form a gel, and control the molar ratio of Na2O, Al2O3 and SiO2 in the gel to be 1.5:1:5.8; After stirring for 30min, transfer into the synthesis kettle, crystallize at 96℃ for 36h, filter the obtained solid, wash with deionized water until the pH of the washing liquid is 10.1, then dry at 120℃ for 12h to obtain Y-type molecular sieve.

[0102] Example 4

[0103] The embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0104] Take 500g water glass, slowly add 300g of the above silicon aluminum glue 4, add 132g of the above directing agent 4, stir for 30min, then slowly add aluminum nitrate, stir for 20min, and finally add sodium aluminate solution 4 to form a gel, and control the molar ratio of Na2O, Al2O3 and SiO2 in the gel to be 1.1:1:6.0; After stirring for 30min, transfer into the synthesis kettle, crystallize at 98℃ for 32h, filter the obtained solid, wash with deionized water until the pH of the washing liquid is 10.3, then dry at 120℃ for 12h to obtain Y-type molecular sieve.

[0105] Example 5

[0106] The embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0107] Take 550 g of water glass, slowly add 340 g of the above silica alumina sol 5, then add 148 g of the above directing agent 5, stir for 30 min, then slowly add aluminum acetate, stir for 20 min, and finally add the above fresh sodium metaaluminate solution 5 to form a gel, and control the molar ratio of Na2O, Al2O3, SiO2 in the gel to be 1.6:1:5.3; After rapid stirring for 30 min, it is transferred into a synthesis kettle, crystallized at 97°C for 26 h, the obtained solid is washed with deionized water until the pH of the washing liquid is 10.4, and then dried at 120°C for 12 h to obtain Y molecular sieve.

[0108] Example 6

[0109] The embodiment provides a Y molecular sieve synthesis method, and the specific steps are as follows:

[0110] Take 350 g of water glass, slowly add 167 g of the above silica alumina sol 6, then add 102 g of the above directing agent 6, stir for 30 min, then slowly add aluminum formate, stir for 20 min, and finally add the sodium metaaluminate solution 6 to form a gel, and control the molar ratio of Na2O, Al2O3, SiO2 in the gel to be 1.8:1:5.9; After rapid stirring for 30 min, it is transferred into a synthesis kettle, crystallized at 95°C for 22 h, the obtained solid is washed with deionized water until the pH of the washing liquid is 10.5, and then dried at 120°C for 12 h to obtain Y molecular sieve.

[0111] Example 7

[0112] The embodiment provides a Y molecular sieve synthesis method, and the specific steps are as follows:

[0113] Take 550 g of water glass, slowly add 345 g of the above silica alumina sol 7, then add 190 g of the above directing agent 7, stir for 30 min, then slowly add aluminum sulfate solution with a concentration of 90 g / L, stir for 20 min, and finally add the sodium metaaluminate solution 7 to form a gel, and control the molar ratio of Na2O, Al2O3, SiO2 in the gel to be 1.4:1:5.0; After rapid stirring for 30 min, it is transferred into a synthesis kettle, crystallized at 97°C for 20 h, the obtained solid is washed with deionized water until the pH of the washing liquid is 10.0, and then dried at 120°C for 12 h to obtain Y molecular sieve.

[0114] Example 8

[0115] The embodiment provides a Y molecular sieve synthesis method, and the specific steps are as follows:

[0116] Take 350 g of water glass, slowly add 167 g of the above silica alumina sol 8, then add 100 g of the above directing agent 8, stir for 30 min, then slowly add aluminum fluoride, stir for 20 min, and finally add sodium metaaluminate solution 8 to form a gel, and control the molar ratio of Na2O, Al2O3, SiO2 in the gel to be 1.7:1:5.4; After rapid stirring for 30 min, it is transferred into a synthesis kettle, crystallized at 92°C for 38 h, the obtained solid is washed with deionized water until the pH of the washing liquid is 10.3, and then dried at 120°C for 12 h to obtain Y molecular sieve.

[0117] Example 9

[0118] This example provides a Y molecular sieve synthesis method, and the specific steps are as follows:

[0119] Take 390 g of water glass, slowly add 160 g of the above silica alumina sol 9, then add 140 g of the above directing agent 9, stir for 30 min, then slowly add aluminum formate, stir for 20 min, and finally add sodium metaaluminate solution 9 to form a gel, and control the molar ratio of Na2O, Al2O3, SiO2 in the gel to be 1.7:1:5.7; After rapid stirring for 30 min, it is transferred into a synthesis kettle, crystallized at 100°C for 20 h, the obtained solid is washed with deionized water until the pH of the washing liquid is 10.2, and then dried at 120°C for 12 h to obtain Y molecular sieve.

[0120] Example 10

[0121] This example provides a Y molecular sieve synthesis method, and the specific steps are as follows:

[0122] Take 290 g of water glass, slowly add 120 g of the above silica alumina sol 10, then add 110 g of the above directing agent 10, stir for 30 min, then slowly add aluminum nitrate, stir for 20 min, and finally add the above fresh sodium metaaluminate solution 10 to form a gel, and control the molar ratio of Na2O, Al2O3, SiO2 in the gel to be 1.2:1:5.6; After rapid stirring for 30 min, it is transferred into a synthesis kettle, crystallized at 94°C for 30 h, the obtained solid is washed with deionized water until the pH of the washing liquid is 10.4, and then dried at 120°C for 12 h to obtain Y molecular sieve.

[0123] Example 11

[0124] This example provides a Y molecular sieve synthesis method, and the specific steps are as follows:

[0125] Take 500g of silica sol, slowly add 400g of the above-mentioned silica-alumina sol 1, then add 123g of the above-mentioned directing agent 1, stir for 30 minutes, then slowly add an aluminum sulfate solution with a concentration of 88g / L, stir for 20 minutes, and finally add a sodium metaaluminate solution 1 that has been placed at room temperature for 1 month to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1:1:6; after rapid stirring for 30 minutes, transfer it into a synthesis kettle, crystallize at 100°C for 40 hours, wash the obtained solid with deionized water until the pH of the washing liquid is 10.5, and then dry at 120°C for 12 hours to obtain a Y-type molecular sieve.

[0126] Example 12

[0127] The present embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0128] Take 200g of white carbon black, slowly add 100g of the above-mentioned silica-alumina sol 2, then add 78g of the above-mentioned directing agent 2, stir for 30 minutes, then slowly add aluminum chloride, stir for 20 minutes, and finally add a sodium metaaluminate solution 2 that has been placed at room temperature for 1 month to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.9:1:5.8; after rapid stirring for 30 minutes, transfer it into a synthesis kettle, crystallize at 96°C for 36 hours, wash the obtained solid with deionized water until the pH of the washing liquid is 10.2, and then dry at 120°C for 12 hours to obtain a Y-type molecular sieve.

[0129] Example 13

[0130] The present embodiment provides a Y-type molecular sieve synthesis method, and the specific steps are as follows:

[0131] Take 350g of water glass, slowly add 167g of the above-mentioned silica-alumina sol 8, then add 100g of the above-mentioned directing agent 8, stir for 30 minutes, then slowly add aluminum fluoride, stir for 20 minutes, and finally add a sodium metaaluminate solution 8 that has been placed at room temperature for 1 month to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.7:1:5.4; after rapid stirring for 30 minutes, transfer it into a synthesis kettle, crystallize at 92°C for 38 hours, wash the obtained solid with deionized water until the pH of the washing liquid is 10.3, and then dry at 120°C for 12 hours to obtain a Y-type molecular sieve.

[0132] Comparative Example 1

[0133] The Y-type molecular sieve synthesis method provided in the present comparative example is similar to that of Example 3, except that the sodium metaaluminate solution is different, and the directing agent is prepared using the sodium metaaluminate solution in the present comparative example. The Y-type molecular sieve synthesis method provided in the present comparative example includes the following steps:

[0134] Sodium aluminate solution D-1: 40 wt% sodium hydroxide solution and aluminum hydroxide powder with an Al2O3 content of 90 wt% were reacted in an autoclave at 0.3 MPa and 100 °C for 2 hours. The molar ratio of Al2O3 to Na2O was controlled at 1:1.08. The concentration of Al2O3 in this sodium aluminate solution was 150 g / L and the concentration of Na2O was 99 g / L.

[0135] Directing agent D-1: Weigh 180g of the above fresh sodium aluminate solution D-1, and slowly add silicon powder (calculated as SiO2, the molar ratio of silicon powder to directing agent is 0.01), water glass, and solid sodium bicarbonate (calculated as alumina, the amount of this alkali added accounts for 5% of the total mass of the directing agent). Let it stand at 33℃ for 18 hours to age, and a directing agent with a molar ratio of Na2O, Al2O3, and SiO2 of 20:1:15 is prepared.

[0136] Weigh 300g of water glass, slowly add 140g of the above-mentioned aluminosilicate 3, then add 112g of the above-mentioned directing agent D-1, stir thoroughly for 30min, then slowly add aluminum phosphate, stir for 20min, then add the above-mentioned fresh sodium aluminate solution D-1 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.5:1:5.8; stir rapidly for 30min, then transfer to a synthesis vessel, crystallize at 96℃ for 36 hours, filter the obtained solid and wash it with deionized water until the pH of the washing solution is 10.1, then dry at 120℃ for 12h to obtain Y-type molecular sieve.

[0137] Comparative Example 2

[0138] This comparative example is similar to Example 8, except that silica powder was not added during the preparation of the directing agent. The Y-type molecular sieve synthesis method provided in this comparative example includes the following steps:

[0139] Directing agent D-2: Weigh 400g of the above fresh sodium aluminate solution 8, and add water glass and solid sodium carbonate (the amount of the alkali added accounts for 9% of the total mass of the directing agent based on alumina). Let it stand at 36°C for 10 hours to age, and a directing agent with a molar ratio of Na2O, Al2O3 and SiO2 of 13:1:18 is prepared.

[0140] Weigh 350g of water glass, slowly add 167g of the above-mentioned aluminosilicate 8, then add 100g of the above-mentioned directing agent D-2, stir thoroughly for 30min, then slowly add aluminum fluoride, stir for 20min, and finally add sodium aluminate solution 8 to form a gel, and control the molar ratio of Na2O, Al2O3, and SiO2 in the gel to be 1.7:1:5.4; stir rapidly for 30min, then transfer to a synthesis vessel, crystallize at 92℃ for 38 hours, filter the obtained solid and wash it with deionized water until the pH of the washing solution is 10.3, and then dry it at 120℃ to obtain Y-type molecular sieve.

[0141] Comparative Example 3

[0142] The Y-type molecular sieve synthesis method provided in this comparative example is similar to that in Example 1, except that the sodium metaaluminate solution used is different. The Y-type molecular sieve synthesis method provided in this comparative example comprises the following steps:

[0143] Sodium metaaluminate solution D-3: 25wt% sodium hydroxide solution was reacted with aluminum hydroxide powder with an Al2O3 content of 60wt% in an autoclave at 0.4MPa and 140°C for 6 hours, and the molar ratio of Al2O3 to Na2O was controlled to be 1:0.86. The Al2O3 concentration in the sodium metaaluminate solution was 150g / L, and the Na2O concentration was 79g / L.

[0144] Directing agent D-3: 100g of the above fresh sodium metaaluminate solution D-3 was weighed out, and silicon powder (the molar ratio of the silicon powder to the directing agent was 0.2, calculated as SiO2), water glass, and solid sodium hydroxide (the amount of the alkali added accounted for 1% of the total mass of the directing agent, calculated as alumina) were added thereto. The mixture was aged at 35°C for 23 hours to prepare a directing agent with a molar ratio of Na2O:Al2O3:SiO2 of 10:1:10.

[0145] 500g of silica sol was slowly added to 400g of the above silicon-aluminum sol 1, and then 123g of the above directing agent D-3 was added. After being stirred for 30 minutes, an aluminum sulfate solution with a concentration of 88g / L was slowly added, and after being stirred for 20 minutes, the above sodium metaaluminate solution D-3 that had been left to stand at room temperature for 10 days was added to form a gel, and the molar ratio of Na2O:Al2O3:SiO2 in the gel was controlled to be 1:1:6. After being stirred rapidly for 30 minutes, the mixture was transferred into a synthesis autoclave, and crystallization was carried out at 100°C for 40 hours. The solid obtained by filtration was washed with deionized water, and the pH of the washing liquid was 10.5. Then, the solid was dried at 120°C for 12 hours to obtain a Y-type molecular sieve.

[0146] Comparative Example 4

[0147] This comparative example is similar to Example 5, except that the silicon-aluminum gel is different. The Y-type molecular sieve synthesis method provided in this comparative example comprises the following steps:

[0148] Silicon-aluminum sol D-4: A NaY mother liquor with a SiO2 concentration of 44g / L and a Na2O concentration of 24g / L was aged with aluminum acetate at 50°C for 150 minutes, and a silicon-aluminum sol was prepared by filtration and washing. The mass data of the silicon-aluminum sol were as follows: SiO263%, Al2O319%, Na2O 12%, solid content 10%, and density 1.13.

[0149] Take 550 g of water glass, slowly add 340 g of the above silicon aluminum colloid D-4, then add 148 g of the above directing agent 5, stir for 30 min, then slowly add aluminum acetate, stir for 20 min, then add the above fresh sodium metaaluminate solution 5 to form a gel, and control the molar ratio of Na2O, Al2O3 and SiO2 in the gel to be 1.6:1:5.3; after rapid stirring for 30 min, transfer into a synthesis kettle, crystallize at 97℃ for 26 h, wash the obtained solid with deionized water until the pH of the washing liquid is 10.4, then dry at 120℃ for 12 h to obtain Y molecular sieve.

[0150] Comparative Example 5

[0151] The Y molecular sieve synthesis method provided by the present comparative example comprises the following steps:

[0152] Sodium metaaluminate solution D-5: 500 ml of sodium hydroxide solution with a concentration of 31.8% and 223.8 g of aluminum hydroxide powder with an Al2O3 content of 62.7% are added to a stirred reaction kettle, the reaction pressure is 0.2 MPa, the reaction temperature is 125℃, and the reaction time is 6 hours to prepare the used sodium metaaluminate solution.

[0153] Silicon aluminum colloid D-5: The filtered filtrate of the aging qualified material in the NaY preparation step with a SiO2 concentration of 45.8 g / L and a Na2O concentration of 25.2 g / L is reacted with an aluminum sulfate solution with an Al2O3 concentration of 90.2 g / L, and the silicon aluminum colloid is prepared after filtration and washing. The mass data of the silicon aluminum colloid are as follows: SiO2 61.9%, Al2O3 16.6%, Na2O 13.7%, solid content 11.9%, and density 1.0956.

[0154] Directing agent D-5: 135.6 ml of sodium metaaluminate solution with an Al2O3 concentration of 150.5 g / L and a Na2O concentration of 180.3 g / L and 270.6 ml of liquid alkali with a concentration of 31% are added to a stirred reaction kettle, stirred uniformly, then 718.2 ml of water glass solution with a SiO2 concentration of 250.6 g / L and a modulus of 3.25 is added, the aging temperature is controlled at 28℃, and the aging is performed for 20 hours. After aging, 169 ml of chemical water is added, and the obtained product is the directing agent solution.

[0155] Take 255.9 ml of the above silica alumina gel D-5, water glass solution 294.2 ml (the SiO2 concentration in the water glass solution is 250.6 g / L, and the modulus is 3.25), 52.8 ml of the above fresh sodium metaaluminate solution D-5, 50 ml of the directing agent D-5, and 65.8 ml of an aluminum sulfate solution with an Al2O3 concentration of 90.5 g / L, and add them into a gelation reaction kettle in a certain flow rate and in a concurrent manner, so as to ensure that the molar ratio of Na2O, Al2O3, and SiO2 is 2-3.5:1:8-10, the stirring time is 40 minutes, the temperature is raised to 98 ℃, and the obtained product is aged for 28 hours. Then, the Y-type molecular sieve is obtained by washing and filtering the product.

[0156] The Y-type molecular sieves prepared in each of the examples and the comparative examples are subjected to detailed comparison in terms of crystallinity, silica alumina ratio, total pore volume, salt emission reduction amount, and total cost reduction amount. The salt emission reduction amount and the total cost reduction amount are based on Comparative Example 5, and the specific results are shown in Table 1.

[0157] Table 1

[0158]

[0159]

[0160] As can be seen from the data in the above table, by comparing Example 3 with Comparative Example 1, the instability problem of the sodium metaaluminate solution is fundamentally solved after the addition of the stabilizer, the salt emission amount and the total cost are reduced by about 12% and 16% respectively compared with Comparative Example 1 while ensuring high crystallinity of the molecular sieve. In addition, as can be seen from the comparison results of Example 8 and Comparative Example 2, after the addition of the silicon powder during the preparation of the directing agent, the silicon island is fully utilized to aggregate and promote crystallization and synthesis, so that the crystallinity of the Y-type molecular sieve is increased by 17 units. As can be seen from the comparison of Example 1 and Comparative Example 3, if the stabilizer is not added, the sodium metaaluminate solution is easily resolved to contain aluminum compounds, which leads to failure, poor synthesis efficiency, and thus affects the synthesis effect, the crystallinity is reduced from 90% to 80%, which significantly affects the synthesis effect, and the total cost reduction rate is low. As can be seen from the comparison of Comparative Example 4 and Example 5, the natural mineral is activated and acid-treated in the present application, which not only can be used as an aluminum source, but also can significantly increase the total pore volume. Although Comparative Example 5 can ensure smooth crystallization, it does not have advantages in terms of salt emission and total cost reduction because it is not a low-sodium gel.

[0161] In summary, the preparation method of the Y-type molecular sieve provided by the present application can obtain a molecular sieve with high silica alumina ratio and mesopores, and the salt emission amount is greatly reduced, and the total synthesis cost is also significantly reduced. The present application has a more broad application prospect while reducing the cost and increasing the efficiency.

[0162] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, and these corresponding changes and modifications shall all belong to the protection scope of the claims of the present application.

Claims

1. A process for preparing a Y-type molecular sieve containing mesopores, characterized by, The method comprises the following steps: The silicon source, the directing agent and the silica alumina gel are mixed uniformly, then the aluminum source and the sodium metaaluminate solution are added to form a gel, and the Y-type molecular sieve is obtained through crystallization and post-treatment; The directing agent is obtained by mixing and aging a sodium metaaluminate solution, silicon powder, a silicon source and an alkaline compound; The silica alumina gel is obtained by mixing and aging an activated and acid-treated natural mineral and a NaY mother liquor; The sodium metaaluminate solution used in the formation of the gel and the preparation of the directing agent is the same, the sodium metaaluminate solution contains a stabilizer, the concentration of Al2O3 is 190-400 g / L, the concentration of Na2O is 210-400 g / L, and the molar ratio of Na2O to Al2O3 is controlled to be 0.86-3.46:1, The molar ratio of Na2O, Al2O3 and SiO2 in the gel is (1.0-1.9):1:(5-7); The stabilizer is selected from one or more of sodium carbonate, sodium bicarbonate and ammonia.

2. The production method according to claim 1, wherein The acid treatment is that the activated natural mineral is treated with an acid solution at 20-100 ℃ and pH 2.8-6.0 for 10-90 min; The concentration of the acid solution is 0.1-15 mol / L; The liquid-solid ratio of the activated natural mineral to the acid solution is 4-15.

3. The production method according to claim 1, wherein The activation temperature is 600-900 ℃, and the activation time is 20-100 min.

4. The production method according to claim 2, wherein The natural mineral is selected from one or more of soft and hard kaolin, coal-based kaolin, halloysite, attapulgite, sepiolite and palygorskite; The acid solution is selected from an inorganic acid solution or an organic acid solution, the inorganic acid is selected from one or more of sulfuric acid, hydrochloric acid, nitric acid and phosphoric acid, and the organic acid is selected from one or more of formic acid, citric acid, oxalic acid and acetic acid.

5. The production method according to claim 1, wherein In the preparation of the silica alumina gel, the aging temperature is 20-100 ℃, and the aging time is 10-240 min.

6. The production method according to claim 1, wherein The concentration of SiO2 in the NaY mother liquor is 40-65 g / L, and the concentration of Na2O is 20-40 g / L; The mass data of the silica alumina gel are as follows: SiO2 50%-65%, Al2O3 15%-20%, Na2O 12-15%, solid content 10%-50%, and density 1.0-1.

4.

7. The production method according to claim 1, wherein The sodium metaaluminate solution is obtained by reacting a 25wt%-50wt% sodium hydroxide solution with an aluminum hydroxide powder with an Al2O3 content of not less than 60wt% at 0.1-0.4 MPa and 100-140 ℃, and then adding a stabilizer; The mass of the stabilizer added is 1%-10% based on the total mass of the sodium hydroxide solution and the aluminum hydroxide powder being 100%.

8. The production method according to claim 1, wherein The molar ratio of Na2O, Al2O3 and SiO2 in the directing agent is (10-20):1:(10-20); The preparation of the directing agent comprises the following steps: the alkaline compound, the silicon powder and the silicon source are added to the sodium metaaluminate solution, and then the mixture is uniformly mixed and aged at 30-40 ℃ for 6-24 hours.

9. The production method according to claim 8, wherein The alkaline compound is selected from any one of sodium hydroxide, sodium carbonate and sodium bicarbonate. The mass ratio of the alkaline compound to the directing agent, calculated as Al2O3, is 0.01-0.1; The molar ratio of the silicon powder to the directing agent, calculated as SiO2, is 0.01-0.

2.

10. The production method according to claim 1, wherein The crystallization is hydrothermal crystallization, the temperature of the hydrothermal crystallization is 90-100℃, and the time is 16-40h.

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